Liberty of Indifference (liberum arbitrium indifferentiae) is for some philosophers an effort to identify "liberty" as merely some form of indeterminism or chance. This argument is popular with determinist and compatibilist philosophers who want to show that this kind of free will is "not worth having," in Daniel Dennett's apt phrase.

For some philosophers of mind, it is an example of a mechanical equilibrium so finely balanced that even an immaterial mind could push the body in one direction or the other.

Liberty of Indifference was very popular among the Scholastics and is discussed extensively by rationalists like Descartes and Spinoza, and by empiricists like Locke, Berkeley, and Hume. It plays a large role in Schopenhauer's prize essay On the Freedom of the Will.

The metaphor of an unrealizable perfect balance is popular among philosophers, whose model for mental actions is the resolution of forces like motives or desires. Is the will paralyzed when presented with identical choices? Of course there is no such thing as perfectly identical alternatives, but from ancient times philosophers argued this case, starting with Aristotle.

"there is this necessity of indifference...of the man who, though exceedingly hungry and thirsty, and both equally, yet being equidistant from food and drink, is therefore bound to stay where he is." (De Caelo, Book II, Sect.13, 295b31-33

Aristotle assumed it was obvious that the man would not starve. He used this argument as a sort of reductio ad absurdum. But later Scholastics took this argument very seriously, especially the logician Jean Buridan, who is said to have given the example of an ass placed equidistant between two identical bales of hay. Buridan used it to show a critical difference between man and animals.

The Scholastics claimed the ass would starve to death (which is nonsense), but a human in similar circumstances, with a god-given gift of free will (in this case the liberty of indifference?) would deliberate and choose despite the perfect balance* between identical alternative possibilities.

* There is an interesting etymological connection between the Latin verbs for balance (librare) and liberate (liberare). The English words deliberate and deliberation - and the Latin deliberatio - is normally derived from the Latin delibrare (to balance) but it has a claim to a derivation from deliberare, in which case its meaning might be to de-liberate among alternative possibilities, or un-free one of those possibilities as the determinate willed action.

Liberty of Indifference was often contrasted with Liberty of Spontaneity, another name for the "negative freedom" when one is free from constraints. Liberty of Spontaneity was also called Voluntarism and today is knowns as Freedom of Action. For classical compatibilists like Hume, Voluntarism or Liberty of Spontaneity is compatible with determinism. Since the agent's will is in the causal chain of events, it is one of the causes and that is enough for compatibilist free will.

Liberty of Indifference, by contrast, was considered a "positive freedom," first, to choose to act or not to act, and in more sophisticated libertarian positions, to choose from alternative actions.

Liberty of Indifference thus raises the question whether one could have done otherwise. Compatibilists maintain that if this were the case, responsibility would not be possible, since it requires determination by reasons, motives, desires, etc, in short determination by an agent's character.

For David Hume, any liberty at all depends entirely on chance. Hume mistakenly generalized from the Liberty of Indifference where a random choice is quite rational between identical alternatives. He says that liberty is absurd and unintelligible, because it denies causality and necessity:

I believe we may assign the three following reasons for
the prevalence of the doctrine of liberty, however absurd it
may be in one sense, and unintelligible in any other. First,
After we have perform'd any action; tho' we confess we
were influenc'd by particular views and motives; 'tis difficult
for us to persuade ourselves we were govern'd by necessity,
and that 'twas utterly impossible for us to have acted otherwise; the idea of necessity seeming to imply something of
force, and violence, and constraint, of which we are not
sensible. Few are capable of distinguishing betwixt the
liberty of spontaneity, as it is call'd in the schools, and the
liberty of indifference; betwixt that which is oppos'd to violence, and that which means a negation of necessity and
causes.
(Treatise on Human Nature, Book II, Part III, Sections I-II, p.407)

For Hume, liberty (chance) eliminates causality and necessity. The first compatibilist, Chrysippus, had settled for fate and determinism, while denying necessity. He agreed with Aristotle that necessity and freedom were incompatible.

The modern compatibilists, Hobbes and Hume, restored necessity to their compatibilism and began the trend among modern philosophers, especially those who favor Hume's naturalism, to call free will unintelligible.

Arthur Schopenhauer's essay "On the Freedom of the Will" won the prize of the Royal Danish Academy of Sciences in 1839. His description of his predecessors' work (pp. 65-90) is extensive.
Schopenhauer defined absolute freedom - the liberum arbitrium indifferentiae - as not being determined by prior events. "Under given external conditions, two diametrically opposed actions are possible." He found this completely unacceptable.

If we do not accept the strict necessity of all that happens by means of a causal chain which connects all events without exception, but allow this chain to be broken in countless places by an absolute freedom, then all foreseeing of the future... becomes...absolutely impossible, and so inconceivable.

The future is of course not foreseeable, but chance is the direct cause of action only in those cases where no clear preference exists, the original and sound idea of a liberty of indifference. In those cases flipping a coin is an appropriate rational action. For all other cases, chance simply contributes creativealternative possibilities for the determined will to choose from with a much broader liberty than the restricted cases of indifference.

Kane developed the idea of dual (or plural) rational control in the case of a “torn decision,” (in which an agent has equally powerful reasons for choosing either way between two alternatives) and yet preserve the sense of responsibility. As long as the agent is prepared to accept responsibility either way, flipping a coin does no harm to practical responsibility. Kane notes that this was first suggested by Steven M. Cahn in 1977, as an argument against the compatibilist claim that any chance involved in a decision would make the decision irrational and irresponsible.

Kane distinguishes choices with "plural rational control" from the ancient Liberty of Indifference in which there is no meaningful differences between the choices, such as the classic idea of Buridan's Ass. And he thinks these examples where indeterminism is "centered" in the decision itself (as Randolph Clarke described it) is completely unacceptable for moral and prudential decisions.

His critics postulate an example where an agent has an identical person in a nearby possible world, with exactly the same past experience, but chooses A instead of B. Surely, the critics say, it is a matter of luck which the agent did, so it is unjust to hold the agent morally responsible for doing the wrong thing.

Kane replied to the critics in a 1999 paper, "Responsibility, Luck, and Chance." There he cited a 1977 article by Steven M. Cahn as the origin of the idea that compatibilists are wrong that any chance makes an agent irresponsible. ("Random Choices," Philosophy and Phenomenological Research,
vol. XXXVII, no. 4, 1977, p.549.)

Kane claims that indeterminism in the brain makes it uncertain as to whether an agent's efforts will succeed. When those efforts do succeed, though indeterminism was involved (thus breaking the deterministic chain), the outcome was undetermined, though not uncaused - it was caused by the agent's efforts, he says.

Suppose two agents had exactly the same pasts up to the point where they were faced with a choice between
distorting the truth for selfish gain or telling the truth at great
personal cost. One agent lies and the other tells the truth... if the pasts of these two agents are really identical in every
way up to the moment of choice, and the difference in their acts results
from chance, would there be any grounds for distinguishing
between them, for saying that one deserves censure for a selfish
decision and the other deserves praise?
Would it be just to reward the one and punish the other for what appears
to be ultimately the luck of the draw?

On the view just described,
you cannot separate the indeterminism from the effort to
overcome temptation in such a way that first the effort occurs followed
by chance or luck (or vice versa). One must think of the effort
and the indeterminism as fused; the effort is indeterminate and the
indeterminism is a property of the effort, not something separate
that occurs after or before the effort. The fact that the woman's effort
of will has this property of being indeterminate does not make
it any less her effort.

And just as expressions like 'She chose by chance' can mislead us
in these contexts, so can expressions like 'She got lucky'. Ask yourself
this question: Why does the inference 'He got lucky, so he was not
responsible' fail when it does fail? The first part of an answer goes back to the claim that
'luck', like 'chance', has question-begging implications in ordinary
language which are not necessarily implications of "indeterminism"
(which implies only the absence of deterministic causation). The
core meaning of 'He got lucky', which is implied by indeterminism, I
suggest, is that 'He succeeded despite the probability or chance of failure';
and this core meaning does not imply lack of responsibility, if he succeeds.

The inference 'He got
lucky, so he was not responsible' fails because what [the agents} succeeded in doing was what they were trying and
wanting to do all along. When they succeeded, their reaction
was not "Oh dear, that was a mistake, an accident—something
that happened to me, not something I did." Rather, they
endorsed the outcomes as something they were trying and wanting
to do all along, that is to say, knowingly and purposefully, not by
mistake or accident.

Here Kane adds a difference in the temporal sequences of the otherwise identical cases. Obviously, this is a difference that makes a difference. It becomes an example of a second (adequately determined) stage (in a two-stage model). The agent's efforts single out the reasons for the ultimate choice.

In one world, one of the efforts
issued in a choice and in the other world, a different effort issued in
a different choice; but neither was merely accidental or inadvertent
in either world. I would go even further and say that we may also
doubt that the efforts they were both making really were exactly the
same. Where events are indeterminate, as are the efforts they were
making, there is no such thing as exact sameness or difference of
events in different possible worlds. Their efforts were not exactly the
same, nor were they exactly different, because they were not exact.
They were simply unique.

Kane is right that the case of perfectly identical lives is just a logical possibility. And any subsequent indeterminism might make the lives diverge. Just after the moment of indeterminism, the agent's choice may have been influenced by this "ingredient" of indeterminism, making the future the product of chance. To avoid this, Kane says that "the agent's efforts are the cause of the choice," that the reasons behind that choice were not causal, but that the choice itself has now retrospectively made it possible to say that "the agent chose for those reasons." In his 33rd thesis on free will, Kane says

the agents (r1) will have had reasons for choosing as they did; (r2) they will have chosen for those reasons; and (r3) they will have made those reasons the ones they wanted to act on more than any others by choosing for them.

(The Significance of Free Will, (1996) p.135)

When Kane puts the indeterminism earlier in the temporal sequence than the results of the agent's efforts, it becomes a two-stage decision process and is free for that reason. If the indeterminism is "centered" in the decision (as Clarke calls it), then it will be an example of the ancient liberty of indifference (or an undetermined liberty as we call it), but the agent can justifiably describe the decision as rational, as Cahn argued, and it is just for society to hold the agent morally responsible.

For Kane, after the fact of indeterminism, to (1) redefine the indeterminism central to the efforts as merely singling out the reasons that the agent "will have chosen for," and to (2) claim that the indeterministic, statistically caused reasons have been (retrospectively) "made those reasons the ones they wanted to act on more by choosing them," seems to be an attempt to rewrite history simply to avoid the stigma associated with the notion of chance. Kane shares what William James called "antipathy to chance."

Despite developing Cahn's insightful idea of randomness in the final decision as not invalidating responsibility, Kane is reluctant to use the argument for moral choices and his Self-Forming Actions. The equal weights of the alternatives suggests to Kane the liberty of indifference - the ass equidistant between two bales of hay. If the decision is simply a practical decision, something as unimportant as deciding between chocolate or vanilla, the mental equivalent of "flipping a coin" is acceptable, says Kane. But if it is a serious moral choice between acting ethically (for Kane, ethical means considering the interests of others) or acting in one's own self-interest, then he is appalled at the idea that such a choice should be made indeterministically, by randomly flipping a coin, for example.

A moral free choice is then simply a free choice that has moral implications. The question of freedom (from determinism) is a question for physicists, physiologists, psychologists, and neuroscientists. The question of morality is one for ethicists and moral philosophers.

The difficulty of articulating a difference beteen free practical choices and free moral choices is compounded because Kane relies on indeterminism to break the chain of determinism in both cases. And he specifically wants quantum indeterminism, which is notorously difficult to locate in the brain/mind.

Notice that Kane has always accepted chance/indeterminism in the first "free" stage of a two-stage model. He agrees that chance in the first "deliberative" stage (as Randolph Clarke calls it) does provide other options for the (adequately determined) decision. But Kane accepts chance in the second "will" stage of free will only for practical choices. What Clarke calls chance "centered" in the decision is acceptable only for practical choices, not for moral choices.

So the question for Kane is, as long as he agrees that indeterministic chance is involved in the final "torn" decision itself, how is that final-stage chance does not make a moral choice (and therefore a Self-Forming Action) random - if final-stage chance makes a practical choice random?

And given that Kane agrees that despite the randomness in the decision, the agent is fully responsible for the choice, which ever way it turns out, why is this not an acceptable description for the responsibility in moral choices? Why does it not explain moral responsibility as well as it explains practical responsibility?

Kane's answer is that a moral choice should not be an event that just happens to the agent, such as waiting for the outcome of a coin flip. Instead, the agent should be actively involved in the decision, which makes it more like agent-causality than event-causality, but Kane appears to oppose agent-causal views. And why shouldn't an agent be just as actively involved in practical decisions?